In medical practices, a physician frequently employs a stethoscope for diagnosing patients. Owing to the diagnosis with a stethoscope, from biological sounds of patients such as vesicular breath sounds, bronchial breath sounds, low tone continuous sounds, squawks and bubbling rales, various pathologies can be grasped. Owing to the biological sounds from a stethoscope, not only pathologies of a heart and a respiratory system, but also various pathologies of other organ and bowel can be grasped.
Recently, there is a stethoscope in which biological sounds are electrically converted and amplified, followed by outputting with a speaker or the like (Published Application in JP: JP-A No. 2005-52521 (paragraph No. [0011] and FIG. 1).